Blood pressure of 150/100 mm of Hg is high. Vertigo and Giddiness post lunch could be because of Acid peptic disease, food allergies ,
post prandial hypotension and other causes.
Next Steps
Decrease intake of salt,
Sugar and carbohydrates. Avoid spicy food.
Avoid lying down immediately after intake of food.
consult a physician and get his BP recorded and proceed as per his advise in case there is no improvement in symptoms.